1. Field of the Invention
The present invention relates to a cooling unit and a projector which includes this cooling unit.
2. Description of the Related Art
In these days, data projectors are used on many occasions as image projection units which project images including images of screens of personal computers and video images, as well as images based on image data which is stored in memory cards on to a screen. In these projectors, light emitted from a light source is collected on to a micromirror display device called a digital micromirror device (DMD) or a liquid crystal plate for projection of color images on to a screen.
Conventionally, the mainstream of these projectors has been those which use a high-intensity discharge lamp as a light source. However, in recent years, there have been made many developments on data projectors which use, as a light source, semiconductor light emitting elements such as LEDs, laser diodes and organic EL devices or luminescent material and like this. However, semiconductor light emitting elements which are adopted as light sources are highly heat dependent, and it is a known characteristic of a semiconductor light emitting element that when the temperature thereof is increased, the efficiency of transformation from electric power to light is deteriorated.
Then, a cooling construction is generally adopted in which the heat of a semiconductor light emitting element is transmitted to a heat sink, and cooling air is sent to radiator fins which are provided in parallel on a base plate portion of the heat sink so that the semiconductor light emitting element is cooled. In addition, other various proposals to cool such a semiconductor light emitting elements with good efficiency have been made (for example, Japanese Unexamined Patent Publication No. 2007-201285 (JP-A-2007-201285).
A projector disclosed in JP-A-2007-201285 includes a light source unit in which two semiconductor light emitting elements are heat connected individually to two heat sinks. In this light source unit, the two heat sinks are disposed so that heat radiating directions therefrom become opposite to each other, whereby the cooling efficiency can be increased by preventing the interference of heat dissipation. In this construction, however, the heat sinks are cooled individually, and therefore, it has been difficult to reduce the overall size of the projector.